Activation mapping from the coronary sinus may be limited by anatomic variations

Area of Science:

• Anatomy
• Cardiovascular Science
• Medical Imaging

Background:

• The mitral annulus (MA) and coronary sinus (CS) are critical structures in cardiac anatomy.
• Accurate knowledge of their spatial relationship is essential for cardiac procedures and research.

Purpose of the Study:

• To investigate the detailed anatomic relationship between the mitral annulus (MA) and the coronary sinus (CS).
• To quantify the distance between the MA and CS at various points around the annulus.

Main Methods:

• Autopsy examination of 50 human hearts (31 male, 19 female).
• Sectioning of the mitral annulus perpendicular to its plane, with radial subdivision of the posterolateral block.
• Measurement of the distance (D) from the ventricular endocardium under the MA to the nearest wall of the CS at specific angular intervals.

Main Results:

• The distance (D) between the MA and CS varied significantly across different sections.
• The longest distances were observed at 72 and 108 degrees, corresponding to the left posterolateral free-wall location.
• A common anatomic pattern ('Type C') showed separation and reapproximation of the annulus and sinus.

Conclusions:

• The anatomic configuration between the MA and CS is not uniform and presents variations.
• The longest MA-CS distance occurs at the left posterolateral free wall, potentially influencing CS mapping.
• Electrophysiological data obtained during CS mapping should be interpreted considering these anatomical findings.